package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;


public class SimpleRedisLock implements ILock{
    private StringRedisTemplate stringRedisTemplate;
    public SimpleRedisLock(String name,StringRedisTemplate stringRedisTemplate){
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    //锁的名称
    private String name;
    //锁的前缀
    private static final String KEY_PREFIX = "lock:";
    //线程id前缀
    private static final String ID_PREFIX = UUID.randomUUID().toString(true)+"-";
    //定义lua脚本文件
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    @Override
    public boolean tryLock(Long timeoutSec) {
        //获取当前线程id
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        boolean success = Boolean.TRUE.equals(stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS));
        return success;
    }

    @Override
    public void unlock() {
        //调用lua脚本，保证(判断锁标识和线程标识是否一致与释放锁的)原子性
        //获取当前线程id
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        stringRedisTemplate.execute(UNLOCK_SCRIPT, Collections.singletonList(KEY_PREFIX+name), threadId);
    }

    /* @Override
    public void unlock() {
        //获取线程的标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        //判断标识是否一致
        if (threadId.equals(id)){
            //释放锁
            stringRedisTemplate.delete(KEY_PREFIX+name);
        }
    }*/
}
